Imaging Apparatus Ghosting Reduction via Scanning Area Control
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Solution Overview
Problem
Radiation imaging apparatuses using flat panel detectors (FPDs) experience a reduction in image quality due to differences in pixel sensitivity and dark time outputs between scanning areas, leading to ghosting effects when switching between scanning areas.
Innovation Solution
The imaging system performs a first image capturing operation in a smaller scanning area and a second image capturing operation in a larger scanning area, with the control computer adjusting the accumulation time to minimize image artifacts caused by scanning area differences, ensuring the image artifact is below a predetermined allowable value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the scanning area is expanded by switching from a smaller area to a larger area, then the field-of-view is improved, but the pixel sensitivity and dark time output differ between scanning areas causing ghosting effects
Solution Approach 1:
The patent applies preliminary action by performing a dark image output operation before the main image capturing operation. This preliminary operation equalizes the dark time output across all pixels by scanning the entire detector area, ensuring that when the scanning area is expanded, all pixels have been previously exposed to the same dark conditions, thereby eliminating ghosting effects while maintaining uniform pixel sensitivity.
2Area of stationary object
If the scanning area is switched from a smaller area to a larger area, then the coverage is improved, but the dark time output differs between scanned and unscanned areas causing image artifacts
Solution Approach 1:
The patent converts the harmful effect of dark time output differences into a beneficial equalization process. By intentionally performing a dark image output operation that scans the entire area before the main capture, the previously harmful variation in dark time output is transformed into a uniform baseline condition, thereby eliminating image artifacts caused by differential dark time exposure.
3Measurement precision
If the accumulation time is extended to improve signal integration, then the signal-to-noise ratio is improved, but the dark time output increases causing ghosting effects
Solution Approach 1:
The patent applies preliminary action by performing a dark image output operation before the main image capturing operation. This preliminary operation equalizes the dark time output across all pixels by scanning the entire detector area, ensuring that when the scanning area is expanded, all pixels have been previously exposed to the same dark conditions, thereby eliminating ghosting effects while maintaining uniform pixel sensitivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces ghosting effects and maintains image quality by aligning the accumulation times across different scanning areas, preventing significant reductions in image quality during area switching.
Implementation Method 1
a conversion element that converts radiation or light into an electric charge
Data Source
AI summary
An imaging apparatus includes a control unit and a detector that includes multiple pixels and that performs an image capturing operation to output image data corresponding to radiation or light that is emitted. The image capturing operation includes a first image capturing operation in a first scanning area corresponding to part of the multiple pixels to output image data in the first scanning area and a second image capturing operation in a second scanning area larger than the first scanning area to output image data in the second scanning area. The control unit causes the detector to perform an accumulation operation in the second image capturing operation in a time determined so that an image artifact caused by the scanning area is lower than a predetermined allowable value on the basis of information about the amount of integration of accumulation times in the first image capturing operation.